KR20090047779A - Cap assembly and secondary battery using the same - Google Patents

Abstract

The present invention relates to a cap assembly and a secondary battery having the same, and to a cap assembly and a secondary battery having the same, which can prevent an increase in internal resistance and increase the capacity of a cell to the same area.

The cap assembly of the present invention is a cap assembly having a cap up, a PTC and a lower part positioned below the cap up, wherein one side of the cap up is formed with a groove, and the PTC is inserted into the groove. It is done.

In addition, the secondary battery of the present invention accommodates an electrode assembly, and a secondary battery including a can formed with an opening on one side, a cap assembly coupled to the can to seal the can, wherein the cap assembly has a groove on one side. And a formed cap up, a PTC, and a lower part positioned below the cap up, wherein the PTC is inserted into the groove.

Therefore, by inserting the PTC inside the cap up, the cap up and the lower part can be directly welded and integrated. In addition, since the internal resistance due to contact between components can be reduced, and the space occupied by PTC can be reduced, it is possible to increase the capacity of the cell.

 Cap Assembly, Cap Up, PTC, Welding, Internal Resistance, Capacity

Description

Cap assembly and secondary battery having the same {Cap assembly and secondary battery using the same}

The present invention relates to a cap assembly and a secondary battery having the same, and to a cap assembly and a secondary battery having the same, which can prevent an increase in internal resistance and increase the capacity of a cell to the same area.

Currently, with the spread of portable electronic devices such as portable telephones, notebook computers, camcorders, PDAs, and the like, development of secondary batteries used as power sources of these electronic devices is actively progressing.

Such secondary batteries include various types such as nickel-cadmium batteries, lead storage batteries, nickel-hydrogen batteries, lithium ion secondary batteries, and lithium polymer secondary batteries.

Among these, lithium secondary batteries have been widely used in many fields of recent electric / electronic devices because of their advantages such as small size and large capacity, high operating voltage, and high energy density per unit weight.

The lithium secondary battery may be divided into a can type and a pouch type according to the shape of the outer material accommodating the electrode assembly, and the can type may be further divided into a rectangular shape and a cylindrical shape.

Among these, the cylindrical secondary battery is composed of a can assembly forming an outer appearance and a cap assembly coupled to an upper opening of the can via an insulating gasket, and is formed by accommodating an electrode assembly and an electrolyte composed of a positive electrode plate, a negative electrode plate, and a separator inside the can. .

The cap assembly is a stack of cap ups acting as vents, current breakers, PTCs, and electrode terminals, coupled to the top opening of the can, or other components other than the cap up are integrally joined, and then the cap up together with the cap up. Coupled to the top opening.

Recently, in order to reduce the contact resistance between components and simplify the process, a method of integrating the structure of the electrode assembly has been proposed, and as a unitary method, a caulking method and a welding method are frequently used.

However, the welding method is difficult to form integrally, including the cap up, and the reason is that the PTC is located between the cap up and the current breaker due to the structure of the configuration of the cap assembly is changed by the heat is easy to weld Because you can not.

The present invention for solving the problems of the prior art as described above in the cap assembly having a cap up, PTC and a lower part located below the cap up, a groove is formed on one side of the cap up, the groove And a cap assembly into which the PTC is inserted.

In addition, the present invention accommodates an electrode assembly, the secondary battery including a can assembly having an opening formed on one side, the cap assembly coupled to the can to seal the can, the cap assembly is a cap up groove formed on one side And a lower part positioned below the PTC and the cap up, wherein the PTC is inserted into the groove.

The groove of the present invention is characterized in that formed on the surface (lower surface) facing the lower component of the cap up.

The present invention is characterized in that the entire PTC is inserted into the groove.

The present invention is characterized in that a portion of the PTC is inserted into the groove.

The lower part of the present invention is characterized in that it comprises a current breaker located in the lower portion of the cap up and a vent located in the lower portion of the current breaker.

The lower part of the present invention is characterized in that it comprises a vent positioned in the lower portion of the cap up, the cap down and sub-plates in order located in the lower portion of the vent and the insulating material located between the vent and the cap down .

According to the present invention as described above, by inserting the PTC inside the cap up, the cap up and the lower part is directly welded and can be integrated.

In addition, since the internal resistance due to contact between components can be reduced, and the space occupied by PTC can be reduced, it is possible to increase the capacity of the cell.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The details of the object and technical construction of the present invention and the resulting effects thereof will be more clearly understood by the following detailed description with reference to the drawings showing preferred embodiments of the present invention.

In the drawings, distances, thicknesses, and the like of layers and regions may be exaggerated for convenience, and like reference numerals denote like elements throughout the specification.

1 is an exploded perspective view of a rechargeable battery according to a first exemplary embodiment of the present invention, and FIGS. 2A and 2B are combined cross-sectional views of the rechargeable battery of FIG. 1.

1 to 2B, two electrodes 21 and 23 formed in a rectangular plate shape are stacked and wound in a spiral shape to form a jelly roll type electrode assembly 20.

At this time, since the separators 25 are positioned one by one between these electrodes and below or above the two electrodes, the separators 25 are interposed between the two electrodes to be wound to prevent a short circuit between the two electrodes.

Each of the electrode plates 21 and 23 is formed by coating a positive electrode active material or a negative electrode active material slurry on a current collector plate made of a metal foil or a metal mesh made of aluminum or copper.

The slurry is usually formed by stirring a granular active material, auxiliary conductor, binder, plasticizer, and the like in a state where a solvent is added. The solvent is removed in the subsequent electrode formation process.

In the direction in which the electrode plate is wound, a portion of the current collector is formed with an uncoated portion in which a slurry is not applied. On the uncoated portion, electrode tabs 27 and 29 are provided one by one on the electrode plate, and the electrode tabs 27 and 29 are formed so that one is drawn upward in the opening direction of the can 10 and the other is drawn downward. do.

In some cases, a plurality of electrode tabs may be provided on one electrode plate.

The can 10 is formed in various shapes such as a cylinder or a square, and is formed by a deep drawing method using an iron material, an aluminum alloy, or the like.

When the can 10 is formed in a cylindrical shape, a cylindrical side surface is formed to form a cylindrical space for accommodating the electrode assembly, and a lower surface of the cylindrical side surface is formed to block a lower space of the cylindrical side surface. The top of is opened to form an opening.

Subsequently, the electrode assembly 20 is inserted into the can through the opening of the can 10.

In this case, before inserting the electrode assembly 20, the lower insulating plate 11 is first covered on the lower surface of the electrode assembly, and the second electrode tab 29 drawn downward from the electrode assembly 20 bypasses the outer side of the lower insulating plate 11. While being bent in parallel with the bottom of the can 10.

At this time, the electrode assembly 20 forms a cylindrical jelly roll, and the center of the jelly roll is empty to form a hollow.

The center of the lower insulating plate 11 also has a hole in the region corresponding to the hollow of the electrode assembly 20. A portion of the bent downwardly drawn second electrode tab 29 crosses the through hole of the lower insulating plate 11.

In the state provided as described above, the electrode is inserted through the hollow of the electrode assembly from the top to weld the portion of the second electrode tab 29 that crosses the central through hole to be attached to the bottom surface of the can 10.

Therefore, the can 10 has the same polarity as that of the second electrode tab 29, so that the can itself can serve as one electrode terminal.

In some embodiments, the can 10 may be provided in a state in which the center pin 13 is coupled to the hollow of the electrode assembly.

The center pin 13 resists deformation caused by external force in the lateral direction, and becomes a moving passage of gas when an internal abnormality occurs and gas is generated in the electrode assembly, and the charge and discharge of the electrode assembly and the deformation over time. It also serves to increase the life of the battery.

After welding the second electrode tab 29, the upper insulating plate 15 is positioned above the electrode assembly 20, and the first electrode tab 27 of the electrode assembly 20 is connected to the electrode through the through hole of the upper insulating plate 15. Allow it to be pulled out of the assembly.

When the upper insulating plate 15 has a central hole, welding of the second electrode tab 29 may be performed after the upper insulating plate 15 is installed.

Then, the sidewalls of the can are bent into the can to form the beads 17 in accordance with the upper level of the upper insulating plate in the case where the electrode assembly or the upper insulating plate is provided on the can.

The bead 17 prevents the electrode assembly from easily flowing up and down inside the can even in the event of external impact, thereby increasing the reliability of the electrical connection.

Subsequently, electrolyte injection is made over the electrode assembly, which may be done before the beads are formed. Thereafter, an insulating gasket 30 is inserted into the can 10 opening, and the cap assembly 40 is coupled to seal the can 10.

At this time, the insulating gasket 30 is a material having an insulating elasticity, has a form that completely surrounds the outer circumferential surface of the cap assembly 30, and insulates between the cap assembly 30 and the can 10 having different polarities. (10) serves to seal.

The cap assembly 40 may be first installed in the insulating gasket 30 in a form in which each component is combined, or the components may be sequentially stacked in the gasket 30.

The cap assembly 40 according to the first embodiment of the present invention includes a cap up 80 serving as an electrode terminal, a positive temperature coefficient (PTC) 70, and lower parts positioned below the cap up. The breaker may be formed of a current interrupter (CID) 60 that is broken by the action of the vent 50 and the vent 50 electrically connected to the first electrode tab 27 to block a current path.

The cap assembly 40 includes a current interrupter (CID) 60 positioned below the cap up 80 having a groove 81 formed at one side thereof, and a vent 50 located below the current interrupter 60. It consists of a stacked structure in order.

In addition, the PTC 70 is inserted into the groove 81 formed on the lower surface of the cap up 80, that is, the surface facing the current breaker 60, which is a lower component positioned below the cap up 80. .

When the PTC 70 is inserted into the groove 81, the entire PTC 70 can be inserted into the groove 81, as shown in Figure 2a.

Therefore, by inserting the PTC 70 inside the cap up 80, the cap up 80 and the current breaker 60 is in direct contact with each other, so that the cap up 80 and the current breaker 60 are welded. It is possible to integrate.

Therefore, since the PTC 70 is inserted into the groove 81 formed in the cap up 80, it is possible to prevent the internal resistance due to the contact between the components due to flow or the like to increase, and also the PTC 70 occupies Since the space can be reduced, it is possible to increase the capacity of the cell.

In addition, when the PTC 70 'is inserted into the groove 81', only a portion of the PTC 70 'may be inserted into the groove 81', as shown in Fig. 2B.

In this case, there may be a certain amount of space between the cap up 80 ′ and the current breaker 60 to limit the space reduction than when the PTC 70 is completely inserted into the groove 81. It can have better characteristics in controlling the flow of

An insulating material having a thickness of the PTC 70 'not inserted into the groove 81' may be further provided between the current breaker 60 and the cap up 80 '.

The vent 50 interrupts the flow of current by breaking the current breaker 60 when the internal pressure is higher than a predetermined level due to the gas generated in the electrode assembly, and discharges the gas generated by the electrode assembly to the outside.

Then, a crimping operation is performed to seal the can by applying pressure inward and downward to an opening wall of the cylindrical can 10 closed by the cap assembly 40 installed inside the insulating gasket 30.

3A and 3B are cross-sectional views illustrating a configuration of a secondary battery according to a second embodiment of the present invention.

3A and 3B, after receiving the electrode assembly 120 in the can 110, the secondary battery inserts an insulating gasket 130 into the opening of the can 110, and the cap assembly 140 is coupled thereto. And is formed by sealing the can 110.

The components 110 to 130 of the secondary batteries illustrated in FIGS. 3A and 3B have the same configuration as those of the components 10 to 30 of the secondary batteries illustrated in FIGS. 1 and 2B, and play the same role. The description will be omitted.

The cap assembly 140 provided in the secondary battery according to the second embodiment of the present invention includes a cap up 141 having a groove 141a formed at one side thereof, a PTC 142 inserted into the groove 141a, and a cap up ( 141) consists of a lower part located at the bottom.

The lower part is located at the bottom of the cap up 141, the vent 143 including the downwardly convex protrusion 143a, the cap down 144 and the sub-plate 146 sequentially located at the bottom of the vent 143. ).

When the PTC 142 is inserted into a lower surface of the cap up 141, that is, a groove 141a formed on a surface facing the vent 143, which is a lower component positioned below the cap up 141, As shown in FIG. 3A, the entire PTC 142 may be inserted into the groove 141a.

Therefore, the PTC 142 is inserted into the cap up 141 to form a structure in which the cap up 141 and the vent 143 are in direct contact with each other, thereby welding and integrating the cap up 141 and the vent 143. It is possible to.

In addition, since the PTC 142 is inserted into the groove 141a formed in the cap up 141, it is possible to prevent the internal resistance due to contact between components due to flow or the like to increase, and also, the PTC 142 occupies Since the space can be reduced, it is possible to increase the capacity of the cell.

In addition, when the PTC 142 'is inserted into the groove 141b, only a portion of the PTC 142' may be inserted into the groove 141b, as shown in FIG. 3B.

In this case, there is a certain gap between the cap up 141 and the vent 143, so there may be a restriction in reducing the space than when the PTC 142 'is completely inserted into the groove 141b. It may have better properties in controlling it.

An insulating material having a thickness of the PTC 142 ′ that is not inserted into the groove 141b may be further provided between the cap up 141 and the vent 143.

In addition, the vent 143 has a hollow cap down 144 positioned between the insulator 145, and the vent 143 and the cap down 144 are spaced apart from each other by the insulator 145. do.

In addition, the sub plate 146 is positioned below the cap down 144 to cross the hollow formed in the cap down 144, and the sub plate 146 has a protrusion formed in the vent 143 exposed through the hollow ( 143a).

In addition, the upwardly drawn electrode tab 127 of the electrode assembly 120 may be connected to one surface of the cap down 144, or may be connected to one surface of the sub plate 146.

In this case, the bottom surface of the protrusion 143a of the vent 143 may be configured such that when the battery internal pressure increases, the protrusion direction of the protrusion is increased or reversed so that the electrical connection with the sub plate 146 is broken.

In this case, the cap down 144 and the sub plate 146 may be electrically connected by laser welding or the like, and the protrusion 143 and the sub plate 146 of the vent 143 may be electrically connected by ultrasonic welding or the like.

After the cap assembly 140 is coupled to the opening of the can 110, a crimping operation is performed to seal the can 110 by applying pressure inward and downward to the opening wall of the can 110.

The present invention shows a preferred embodiment as described above, but is not limited to the above-described embodiment, various changes by those skilled in the art to which the present invention pertains without departing from the present invention And modifications will be possible.

1 is an exploded perspective view illustrating a configuration of a rechargeable battery according to a first exemplary embodiment of the present invention.

2A and 2B illustrate cross-sectional views of the secondary battery of FIG. 1.

3A and 3B are cross-sectional views illustrating a configuration of a secondary battery according to a second embodiment of the present invention.

[Description of Major Symbols in Drawing]

10, 110: can 11, 111: lower insulation plate

13, 113: center pin 15, 115: phase insulation plate

17, 117: beads 20, 120: electrode assembly

21, 23, 121, 123: electrode plate 25, 125: separator

27, 127: first electrode tab 29, 129: second electrode tab

30, 130: insulating gasket 40, 40 ', 140, 140': cap assembly

50, 143: vent 60: current breaker

70, 70 ', 142, 142': PTC 80, 80 ', 141, 141': Cap Up

81, 81 ′, 141a, 141b: groove 144: cap down

145: insulating material 146: sub plate

Claims (21)

A cap assembly comprising a cap up, a PTC, and a lower component positioned below the cap up, A groove is formed at one side of the cap up, Cap assembly characterized in that the PTC is inserted into the groove. The method of claim 1, And the groove is formed in the lower surface of the cap up. The method of claim 1, And the PTC assembly fully inserted into the groove. The method of claim 1, A cap assembly, wherein a portion of the PTC is inserted into the groove. The method of claim 1, The lower part includes a current breaker located below the cap up; And And a vent located below the current breaker. The method of claim 5, wherein The current breaker is in contact with the bottom surface of the cap up. The method of claim 6, The cap assembly, characterized in that the portion where the current breaker and the lower surface of the cap up is in contact with each other. The method of claim 1, The lower part may include a vent positioned under the cap up; A cap down and a sub plate sequentially positioned below the vent; And And an insulation positioned between the vent and the cap down. The method of claim 8, And the vent is in contact with the bottom surface of the cap up. The method of claim 9, The cap assembly is characterized in that the site where the vent and the lower surface of the cap up is in contact. A secondary battery comprising an electrode assembly accommodating an electrode assembly, a can having an opening formed at one side thereof, and a cap assembly coupled to the can to seal the can. The cap assembly includes a grooved cap up on one side, PTC and a lower part located below the cap up, The secondary battery, characterized in that the PTC is inserted into the groove. The method of claim 11, The electrode assembly may include a first electrode plate having a first electrode tab drawn upwardly in an opening direction of the can; A second electrode plate provided with a second electrode tab drawn out from below the can; And A secondary battery comprising a separator interposed between the first electrode plate and the second electrode plate. The method of claim 11, The groove is a secondary battery, characterized in that formed on the lower surface of the cap up. The method of claim 11, The secondary battery characterized in that the PTC is completely inserted into the groove. The method of claim 11, And a portion of the PTC is inserted into the groove. The method of claim 11, The lower part includes a current breaker located below the cap up; And The secondary battery is positioned below the current breaker and comprises a vent connected to the first electrode tab. The method of claim 16, And the current breaker is in contact with the bottom surface of the cap up. The method of claim 17, The secondary battery, characterized in that the portion where the current breaker and the lower surface of the cap up is in contact with each other. The method of claim 11, The lower part may include a vent positioned under the cap up; A cap down located below the vent; A sub plate positioned under the cap down and connected to the first electrode tab; And And a secondary battery positioned between the vent and the cap down. The method of claim 19, The vent is in contact with the bottom surface of the cap up, characterized in that the secondary battery. The method of claim 20, The secondary battery, characterized in that for welding the portion where the vent and the lower surface of the cap up contact.

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